Model airplane kit



April 27, 1954 Q GOLDBERG 2,676,431

MODEL AIRPLANE KIT Filed May 4 1951 3 Sheets-Sheet 1 April 27, 1954 c.GOLDBERG MODEL AIRPLANE MT 3 SheetsSheet 2 Filed May 4, 1951 April 27,1954 c. GOLDBERG MODEL AIRPLANE KIT CQTZ G'Zfer @ZW WK 3 Sheets-SheetFiled May 4, 1951 Patented Apr. 27, 1954 MODEL AIRPLANE KIT CarlGoldberg, Chicago, Models Inc., a cor IlL, assignor to Top Fiiteporation of Illinois Application May 4, 1951, Serial No. 224,588

1 Claim.

This invention relates to a model kit and more particularly to a modelkit having a number of preformed parts which are to be assembledtogether to complete the model.

One of the features of this invention is the provision of a model kitincluding a number of preformed parts having interengaging means toengage with complementary interengaging means provided on otherpreformed parts so that parts which are to be attached together may becorrectly oriented by bringing the interengaging means into registry. Afurther feature of the invention is to produce a model kit whichincludes a number of similar rightand left-hand or otherwise reversibleparts and to provide each of such parts with dissimilar interengagingmeans for engaging an intervening part not only correctly to orient theparts for attachment to the intervening part, but also to preventreversal of the parts.

A particularly important phase of the inter engagement of the parts isthe interlocking of the fuselage parts, withtop and bottom fuselageparts interlocking at their edges with right and left hand sides of thefuselage. This provides a self-correcting fuselage structure whichensures a properly formed fuselage and which obviates not only bendingor curvature of the entire fuselage to one side or the other, but alsotwisting thereof, despite the initial condition of the parts. Eventhough one or a number of the parts as provided in the kit in die-cutform are twisted or warped to any extent, the mashing of theinterengaging means overcomes any initial warping or differences instrength of the sections and ensures a straight and properly formedfuselage.

A further feature of the invention is the provision of a model airplanekit which includes a preformed wing and to provide such a kit withpreformed ribs each having a cambered surface so that the wing surfaceis properly cambered by attaching the ribs thereto. Another feature ofthe invention is the provision of a model airplane kit of the typedescribed in the preceding sentence with preformed struts to be attachedto the fuselage section of the airplane and to the ribs, correctly todetermine the dihedral of the wings and to control warp thereof.

Another feature of the invention is the provision in a model airplanekit of preformed parts including fuselage side panels and a Wing and toprovide each of the side panels with interengaging means which aredissimilar from each other, with the interengaging means on each paneladapted to be registered with complementary interengaging means on anintervening part to prevent reversal of the side panels and to form afuselage section, and to provide the wing with dissimilar interengagingmeans so that the wing is attachable only in one position to thefuselage section.

Still a further feature of the invention is the provision of wing strutsand interengaging arrangements locating the inner end of the preformedstruts relative to the side of the fuselage and their outer endsrelative to the wing in such manner as to control the warp of the wing.Any undesired warp initially present after the wing is removed from thekit will be corrected by this construction; and any desired warp of oneor both wings, as to counteract the propeller torque or otherwiseimprove flight characteristics will be automatically ensured.

Another feature of the invention is the provision of a model kit of thetype previously described herein, wherein the interengaging meanscomprise a tongue on one part receivable in a slot on the other part sothat the interengaging means serves not only correctly to orient theparts but also forms a part of the securing means for attaching theparts together.

Other and further features of the invention will be apparent from thefollowing disclosure and drawings, in which:

Fig. 1 is a perspective view of a model airplane embodying theinvention;

Fig. 2 is a vertical longitudinal section through the forward portion ofthe fuselage;

Fig. 3 is an elevational view of the landing gear wire;

Fig. 4 is an exploded perspective view showing the manner in which theparts are fitted together; and

Figs. 5 to 26, inclusive, are views showing the preformed parts whichare to be secured together to form the'rnodel airplane.

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawings and will herein be described indetail one specific embodiment, with the understanding that the presentdisclosure is to be considered as an exemplification of the principlesof the invention and is not intended to limit the invention to theembodiment illustrated. The scope of the invention will be pointed outin the appended claims.

For the purposes of'exemplary disclosurathe vention is shown as embodiedin a model air.- plane kit although it will be apparent to those 3skilled in the art that the features may be embodied in other kits formaking models of devices other than airplanes.

Referring now to Figs. 5 to 26 inclusive, the model airplane comprises anumber of preformed parts shown in those figures. Preferably, the partsare stamped from thin sheet balsa so that substantially no cutting orforming of the parts is required of the builder of the model. The partsinclude a right and left-hand fuselage side panel designated RF and LFrespectively, a bottom fuselage section BF, a top fuselage section TF, atop cowl section TC, a bottom cowl section BC, a wing W, a rudder R anda stabilizer S. A number of formers Fl and F4, inclusive, are providedcorrectly to space the fuselage parts from each other and to brace andotherwise strengthen the construction. It will be noted that thesections just referred to are provided with a number of slots andtongues which form the interengaging means for purposes which willhereinafter become apparent. Where parts are apt to be inverted,reversed end for end or right for left, the interengaging means aredissimilar in nature. The dissimilarity in the interengaging means maytake several forms. Thus, the dissimilarity may be in the number ofengaging means or in their relative position or in their shape. In eachcase, where similar parts are formed with dissimilar interengagingmeans, the part to which they are to be attached is formed withinterengaging means which are complementary to the dissimilar engagingmeans and thus parts cannot be misaligned or reversed.

It is believed that the invention is best described by describing thesteps in assembling the parts together to complete the model.

To assemble the kit the first step is to apply cement to the two longsides of the former Fl. It will be noted that the former is providedwith a single tongue 36 on one side and with two tongues 3| and 32 onits opposite side. The tongues 30 to 32, inclusive, form theinterengaging means on the former which are adapted to be inserted intocomplementary slots 30a, 3m and 32a, respectively, in the side panels.It will be noted that the right and left-hand fuselage side panels, RFand LF, are substantially identical, however, the panel RF is providedwith two slots 3la and 32a while the panel LP is provided with but onesuch slot. Thus the parts can only be fitted to the former in thecorrect right and left-hand relationship.

When this step has been completed, the two sections 33 and 34 (Figs. 19and 20) which are similarly formed in the shape of the tail wheel andthe end fuselage section are cemented together to provide a doubleconstruction for the tail wheel. It will be noted. that each of the tailwheel portions is provided with a tongue 35 which, when the parts 33 and34 are cemented together, form a single tongue to be inserted in thenotches 36 formed at the end of the fuselage panels RF and LF. Littleneed for dissimilar interengaging means is required here inasmuch as thetop and bottom of the fuselage are clear and the tail wheel is, ofcourse, on the bottom.

When the cement has dried on the parts just described, the fuselagepanels are slightly spread apart and the bottom fuselage panel BF isslipped into place. It will be noted that the bottom fuselage isprovided with interengaging means in the form of a plurality of tonguesall of which have been designated 38 which are receivable in slots 381on the bottom of the right-hand fuselage section RF and 381 on thelefthand fuselage section LP. The first three of the tongues 38 areequally spaced from each other, but the fourth is positioned closer toits preceding tongue and is also wider. This dissimilarity in. theinterengaging means provided on the section BF, and the complementarydissimilarity found in the slots 38?" and 38L prevents its beinginserted in reversed position. The rear end of the bottom panel BF isprovided with an arrow shaped tongue 39 which fits into a complementaryshaped groove SM, 391 formed on the sections RF and LF, respectively.The forward end of the section BF is provided with a pair of smallertongues 40 which are received in the rear portion of the slots 401' and401, respectively. The tongues 40 fill up only the rear portion of theslots 401", 461 for reasons which will hereinafter become apparent.

In cementing the bottom section BF to the bottom of the right andleft-hand fuselage sections RF and LF, cement may be applied in each ofthe slots mentioned and then the side panels BF and LF spread apart sothat the panel BF may be inserted therebetween with the tongues insertedin each of the slots. When the cement has hardened, which with modelglue is a matter of seconds, not only are the side panels firmly securedtogether but the proper curvature is formed in the fuselage section. Inaddition, the parts are correctly oriented with respect to each otherbecause of the fact that they can be secured together only when theslots and tongues are correctly positioned.

The formers F2, F3 and F4 are next secured in position. For thispurpose, glue may be ap plied to the sides of the former F2 whichincludes the tongues 4i and 42 and then the tongue inserted in the slots4la and 42a, respectively. It will be noted that the tongues 4| and 42are longer than the tongues 30, 3| or 32 so that mispositioning of theformer F2 cannot be achieved. It will also be noted that the slots Maand 42a are slanted, the purpose of which will hereinafter be described.

Glue is then applied to the sides of the former F3 which includes thetongues 43 and 44 and the tongues are inserted in the slots 43a and 44a,respectively, in the sections RF and LP.

The former F4 is provided along its edges with U-shaped notches 45 and45, the upper legs of which fit in the notches 45a and 46a,respectively, in the side panels. The lower legs of the notch extendbeneath the portion of the fuselage side panels carrying the notches 45aand 45a.

The nosepiece N is provided with two tongues 41 and 48 on opposite sidesthereof with the tongues being dissimilarly positioned. Thus it will benoted that the tongue 48 is higher than the tongue 41. Furthermore, thenosepiece N is considerably thicker than the formers inasmuch as it musttake the thrust of the rubber motor used to drive the airplane. Theedges of the nosepiece are cemented and the tongues 4'! and 48 insertedin the notches 41a and 48a, respectively, formed in the front portion ofthe fuselage side panel sections. It will be noted that the notch orslot 41a is deeper than the slot 48a. Thus the nosepiece, when seated,is slightly tilted to the right with respect to the fore-andaft line ofthe aircraft. This is done in order to offset the torque when the rubbermotor is unwinding, the torque tending to pull the airplane to the left.By slightly tilting the propeller to the right, the torque effect whichtends to tilt the airplane to the left, thereby causing it to slip tothe left and thus turn to the left, is offset inasmuch as the offset ofthe propeller tends to turn the airplane to the right resulting in astraight path.

The top fuselage section TB is provided with a number of tongues all ofwhich have been designated as t l, the middle two of which are to beseated in the slots 491* and 491, respectively, of the side panels RFand LF while the right and left-hand tongues 59 seat in cutout portions(for the wing and stabilizer respectively) formed in the tops of theside panels. Again it will be noted that the spacing between the tongues49 is not uniform and thus again the panel can be inserted only inproper position.

It will be noted that the former Pi is provided with a relatively widetongue 50 at its top while the former F t has a narrow tongue 51'similarly positioned. The wing W is provided with complementary portionsfor engaging the tongues 50 and El, namely the slots 59a and did. Thuswhen the wing, which is the next part to be assembled, is placed on thefuselage, its leading and trailing edges cannot be reversed. The narrowslot 51a is adjacent the leading edge of the wing while the broad slotEta is adjacent the trailing edge and hence correct alignment of the.wing is assured and also its alignment with respect to the fuselage isassured inasmuch as the wing can be positioned only when properlyoriented.

The landing gear is in the form of a resilient wire bent generally inthe shape of a U as illustrated in Fig. 3. Thus the landing gear 53 isbent as to have a base 54, a pair of legs 55 and 56 extending from thebase, the legs being bent outwardly intermediate their ends to form theoutwardly extending portions 51 and 58 which in turn are bent at theirends to form the wheel axles 59 and iii]. As shown in Fig. 2, thelanding gear is inserted in the interior of the fuselage and the base51; is cemented to the underside of the wing and front side of theformer F4. Correct positioning of the landing gear is assured bybringing it downwardly from the base into contact with the slantingformer F2 to which it is also cemented. The portions 51 and 58 of thelanding gear are thus positioned to extend outwardly beneath thefuselage.

The cowl bottom BC is illustrated m Fig. and includes the hat panelshown provided with oppositely facing tongues BI, 62, 63 and 64. It isto be attached to the bottom portion of the fuselage section so farcompleted with the tongues 6!, 62 and 63 inserted in the slots Sir, Bil,621", E21, 63r and 631. The tongue 64 is seated in the notches or slotsMr and dill so as to abut the forward end of the bottom fuselage sectionBF.

At this stage of the construction a steel weight 65 may be cemented inthe nose of the airplane on the section BC as shown in Fig. 2. Thisprovides the proper balancing weight for the craft in flight.

The top cowl section TC is provided with an arcuate portion 66 adjacentits rear end with a pair of oppositely facing tongues 61 which arereceived in the notches or slots 611- and 611, respectively, in thefuselage sections. Cement is applied along the two side edges and thefront edge of the section TC, and it is bent around the top curvedportions 68 and 69, respectively, of the nose section N in order to givethe proper curvature to the cowl. The section TC is held in place untilthe cement is hardened, which, as

previously stated, is a comparatively short period of time.

As illustrated in Figs. 21 and 22, the kit may include a pair of ribs 10and H each provided at its ends with tongues 12 and 13, respectively,and with cambered upper surfaces 14 and 15. The wing W is provided withtwo pairs of slots 12a and 12b and 13a and 13b to receive the tongues 12and 13, respectively. Cement is applied along the upper surface of theribs 16 and 1! and then the tongues are inserted in the slots and thewing held in contact with the entire upper surface of the rib. Thisproduces the proper camber in the wing to insure lift to the airfoilsection.

The kit also includes two pairs of struts, the first pair includingprecut struts 15 and 16 and the second pair having the struts 11 and 18.It will be noted that the struts 16 and 18 include a tongue 19 and 80,respectively, which is to be inserted in the grooves SI and 82 formed inthe other strut of the pair. When the pairs of struts are cementedtogether, there is formed a pair of V-shaped struts, each having asingle tongue 83 and 8d at the inner end. The tongues 83 and 84 are tobe inserted into the bottom portions of the notches 831 and 8:11,respectively formed in the left and right-hand fuselage sectionscorrectly to position the struts. The outer ends of the struts areprovided with notches 85 and 85 which are secured to the ends of theribs. The precutting and prealignment of the struts assures that whenthey are inserted in position with the tongues at their inner ends inthe slots 832 and Mr of the fuselage sections and with I changing theactual length of their outer ends encompassing the ends of the ribs, theproper dihedral angle and warp of the Wing are ensured. As will bereadily apparent, the preformed length of the struts and the slotsdetermining their point of location in the side of the fuselage andtheir outer end attachment to the rib and thus to the wing determine notonly the dihedral angle but also the angle of incidence or warp of thewing. Changing the relative length of the front or back struts (as bythe strut in its design, its point of attachment to the side of thefuselage fore and aft, and the distance of one of the ribbed slots 12 or13 from the central wing slots 50a and 5m) enables a predetermined warpof the wing to be achieved. Not only does this correct any undesiredwarp which may be present in the wing before assembly of the plane, butit also enables desired warpage to be designed into the wing, so thatthere may be a deliberate "wash-in to the left wing and wash-out to theright wing, if desired, to offset propellor torone With this portion ofthe airplane completed, the rudder R (Fig. 18), which is provided with aforward tongue 99, a long intermediate tongue 9! and a rear tongue 92,is cemented to the stabilizer S with the tongue fitting into the slot980:, the tongue 9! fitting in the slot em and the tongue 92 fittinginto the slot 92a. The stabilizer is then cemented to the fuselage sidepanels and sits in the cutout portions 93 and 9d of the right andleft-hand sections respectively with the forward portion of the tongue90 fitting in the slot 90b formed on the top fuselage panel TF. Thetongue 92 fills a portion of the slot 92a, the balance of that slotbeing filled by the tongues 85 of the tail wheel sections 33 and 34, itbeing remembered that the tail wheel sections have been previouslycemented together so that the tongue 95 is a single unit. The use oftongue and groove interengaging means in two or more locations ensuresproper alignment of the rudder R, preventing any misalignment withrespect to the axis of the fuselage, and providing certainty of fore andaft location. Similarly, the interengaging assembly of the horizontaltail surface S provides for a predetermined correct angular relationshipbetween this part and the fuselage.

If desired, a windshield 96, which may be of a transparent plastic, maybe cemented in place. To facilitate forming the windshield, it isprovided with an integral tab 99 to be cemented to the leading edge ofthe wing. A lower marginal edge portion 99a is cemented to the cowlsection TC and thence the balance of the plastic material is bent aroundthe side of the fuselage to cover the cabin window openings indicated at97 and 98 and precut in the fuselage side panels.

Wheels may then be slipped onto the axle portions 59 and B and a drop ofcement applied to the outer ends to hold the wheels in place.

A propeller thrust bearing I00 is then seated in a circular opening H3!in the nosepiece N. A propeller I02 which includes a motor hook I03 isthen seated in the bearing and a dowel rod or small peg inserted throughtwo aligned circular openings [0:1 and I05 in the fuselage sidesections. The rear end of the rubber band may be looped around a peginserted in these openings, the alignment of the rubber band beingassisted by the provision of an opening I00 in the top panel T of thefuselage.

When this work has been completed, the airplane is ready to be flown. Itwill be noted that throughout the entire description of the steps ofassembling the model the various tongues and slots have been referred toconstantly. It is believed to be readily apparent that the tongue andslots which form the intergaging means and complementary interengagingmeans of the model will not only prevent misalignment or reversal of theparts, but also serve correctly and accurately to position each partrelative to an adjacent part to which it is to be secured. In manyinstances the parts may be held together merely by inserting the tonguein the slot and then applying cement to the tongue and slot, theinterengaging means serving to hold the parts together as well as toorient them as assembly progresses. Furthermore, the preformed partsserve to produce the proper dihedral angle of the wing and the camber ofthe wing, the correct alignment of the landing gear and the properpositioning of substantially all of the parts of the craft.

The model so constructed may be assembled very rapidly and withsubstantially no chances for error and when so assembled produces asturdy and yet completely accurate scale model.

I claim:

A model airplane kit comprising a plurality of flat precut sheet balsaparts including a unitary wing, a pair of ribs; a pair of struts; andparts to form a fuselage section; at least two slots of unequal lengthformed in the center section of the wing; two pairs of other slots inthe wing with each pair being equidistant from the wingtip in oppositeoutboard sections of the wing; a pair of tongues each complementary to adifferent one of the slots in the center section of the wing and formedin the fuselage portion whereby the wing portion may be placed injuxtaposition with the fuselage portion with the tongues inserted intheir complementary slots to orient the wing and fuselage sections forattachment to each other; a pair of tongues complementary to the pairsof slots formed in each rib, with said ribs each having a camberedsurface to be scoured to the underside of the Wing with the tongues ineach rib inserted in the last mentioned slots to camber the wings andwith said struts to be secured to the fuselage section and to the ribsto determine wing dihedral and warp.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 996,061 Clarke June 27, 1911 1,359,619 Palmer Nov. 23, 19201,776,222 Harris Sept. 16, 1930 1,782,385 Kramer Nov. 18, 1930 1,799,936Tirnson Apr. 7, 1931 1,877,120 Boehme Sept. 13, 1932 2,163,075 WildonJune 20, 1939 2,251,090 West July 29, 1941 2,324,892 Warren July 20,1943 2,510,884 Greene June 6, 1950 FOREIGN PATENTS Number Country Date17,935 Great Britain 1905 685,480 Germany Dec. 18, 1939 OTHER REFERENCESPopular Science Magazine of November 1946, article on page 151.

